量子点光子晶体激光器的理论研究与工艺制备

发布时间：2018-01-08 04:06

本文关键词：量子点光子晶体激光器的理论研究与工艺制备　出处：《中国科学院长春光学精密机械与物理研究所》2016年博士论文　论文类型：学位论文

【摘要】：光子晶体是一种材料折射率周期性变化的微结构,在该结构中可以对光的传播实现有效的控制。光子晶体纳腔激光器因其具有超高的品质因子(Q值)、亚波长量级的模式体积,以及易于集成等优点,在近些年中受到了广泛的关注和研究。以量子点作为增益材料介质的光子晶体纳腔激光器因其具有低阈值、低功耗、高速调制等特点,在片上集成、量子通讯、生物传感等领域有着巨大的应用前景。本文围绕“量子点光子晶体激光器的理论研究与工艺制备”主题,在理论上对1.3-mm In As/Ga As量子点在光子晶体微腔中的载流子动力学、阈值以及调制响应特性进行了系统的研究,在实验上对高Q值、低模式体积Ga As基二维光子晶体纳腔制备中的关键问题展开了一系列研究工作,最后对于耦合纳腔阵列进行了研究讨论。本论文的主要研究内容和创新性如下:1.纳腔效应被首次引入到1.3-mm In As/Ga As量子点全路径弛豫动力学方程中,考虑到高珀赛尔(Purcell)效应下自发辐射因子的增大,光子寿命的提高,以及自发辐射寿命的降低等影响。通过计算得到:高品质因子导致载流子基态占据几率的降低,并且得到阈值对于品质因子的非线性依赖关系;理论上在Q值等于2500时,得到大于100GHz的3d B调制带宽;在Q值为7000时,传输损耗最低。2.对光子晶体结构的色散关系的计算方法进行了具体的介绍和分析,其中重点讨论了平面波展开法和有限时域差分法。其中针有限时域差分法,我们对其边界条件、激励源的设置以及计算的稳定性等进行了详细的研究。3.对光子晶体平板结构的工艺制备过程的关键问题展开了系统的研究工作,主要包括电子束曝光工艺、ICP干法刻蚀工艺以及湿法腐蚀工艺。重点分析了电子束曝光过程中曝光剂量,束流的速度以及步长等对图形的影响,同时对ICP干法刻蚀和湿法腐蚀工艺进行了优化,制备了具有良好形貌的光子晶体平板结构。4.使用有限元差分法(FDTD)对光子晶体纳腔结构进行优化设计,制备了高Q值正六边形耦合光子晶体阵列激光器。该结构通过相邻腔之间的倏逝波耦合,出现多个光学模式,通过对相邻纳腔之间的空气孔的尺寸的调节(即光学势垒),优化出了最高的Q值,这种结构对于解决耦合阵列会降低Q值的问题提供一个有效的方法。
[Abstract]:Photonic crystal is a kind of microstructure with periodic refractive index variation, in which the propagation of light can be controlled effectively. The photonic crystal nanoscale laser has high quality factor Q value. In recent years, the mode volume of sub-wavelength and the advantages of easy integration have received extensive attention and research. The photonic crystal nanoscale laser with quantum dots as the gain material has low threshold because of its low threshold. The characteristics of low power consumption and high speed modulation have great application prospects in the field of on-chip integration, quantum communication, biosensor and so on. This paper focuses on the topic of "theoretical research and fabrication of quantum dot photonic crystal lasers". The carrier dynamics, threshold and modulation response of 1.3-mm in As/Ga as quantum dots in photonic crystal microcavities are studied in theory. A series of research work has been carried out on the key issues in the fabrication of low mode volume GaAs based two-dimensional photonic crystals. Finally, the coupled nanocavity arrays are discussed. The main contents and innovations of this thesis are as follows: 1: 1.The effect of nanocavity is first introduced to 1.3-mm in As/Ga. In the full-path relaxation kinetic equation of as quantum dots. Considering the increase of spontaneous emission factor and the increase of photon lifetime due to the high Purcell effect. Through the calculation, it is found that the high quality factor leads to the decrease of the carrier ground state occupation probability, and the nonlinear dependence of the threshold value on the quality factor is obtained. Theoretically, when Q value is equal to 2500, a 3dB modulation bandwidth greater than 100GHz is obtained. When Q value is 7000, the transmission loss is the lowest. The calculation method of dispersion relation of photonic crystal structure is introduced and analyzed in detail. The plane wave expansion method and the finite-time-domain difference method, in which the needle-finite-time-domain difference method is discussed, and the boundary conditions of the finite time-domain difference method are discussed. The setting of excitation source and the stability of calculation are studied in detail. 3. The key problems in the fabrication process of photonic crystal flat structure are studied systematically, including electron beam exposure process. ICP dry etching process and wet etching process. The effects of exposure dose, beam velocity and step size on the pattern during electron beam exposure are analyzed. At the same time, the dry etching and wet etching processes of ICP were optimized. The photonic crystal plate structure with good morphology was prepared. The finite element difference method (FDTD) was used to optimize the design of photonic crystal nanocavity structure. A high Q-value hexagonal coupled photonic crystal array laser is fabricated. The structure is coupled by evanescent waves between adjacent cavities and many optical modes appear. The maximum Q value is optimized by adjusting the size of the air hole between adjacent nanocavities (i.e. optical barrier). This structure provides an effective method to solve the problem that the coupling array will reduce the Q value.
【学位授予单位】：中国科学院长春光学精密机械与物理研究所
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN248

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